Patent GB-663998-A (GB)
Title: Improvements in shot blasting machines
IPC: B24C3/08
Filed: 1949-08-27
Abstract: 663,998. Shot blasting machines. ST. GEORGE'S ENGINEERS, Ltd., and WLLSON, F. W. Aug: 28, 1950 [Aug. 27, 1949), No. 22333/49. Class 60 [Also in Group XXX] The blasting chamber A of a shot blasting machine primarily for cleaning round and square bars is supplied with abrading material from the hopper or collecting chamber A<SP>1</SP>; dust laden air passes from the chamber A by ducting b to dust arrester B and is exhausted to atmosphere by vertical duct b<SP>1</SP>. A long bed C extending on both sides of the blasting chamber A carries two longitudinal shafts C<SP>1</SP> extending for the whole or substantially the whole length of the bed. Each shaft C<SP>1</SP> carries a series of rollers c spaced at suitable intervals apart, the positions of the rollers c on one shaft coinciding with the positions of the rollers c on the other shaft to form pairs of rollers, with a relatively long interval between the pairs. The rollers c of each pair are spaced a short distance apart and support the bar or the like being treated. The shafts C<SP>1</SP> can be rotated in the same directions by gearing e<SP>1</SP> so as to impart to a supported rod or bar a rotary movement about its longitudinal axis. The bed C also carries a series of transverse shafts E, driven by bevel gearing e from a longitudinal shaft E<SP>1</SP>. Each shaft E carries a cam F lying midway between the shafts C<SP>1</SP>. The normal surface of the cams F lies slightly below the surface of the bar or rod supported by the rollers c but the lift portion of the cams projects sufficiently to engage the bar and rod and lift it clear of the rollers c and consequently feed it longitudinally through the blasting chamber A with a step by step motion. Each cam F is formed of two saucer shaped discs welded together back to back so that the periphery of the cam has a deep groove of substantially V shape in cross-section, arcuate portions being welded or otherwise secured to the two inclined faces of the groove to form the rises or projections; the cams F may be directly welded or otherwise secured on the transverse shafts E or they may be welded or otherwise secured on sleeves adapted to be replaceably secured on the shafts as by set screws, the latter construction being preferred for the cams situated in the interior of the blasting chamber which, being subjected to the abrading action, require frequent replacement. When round bars are being cleaned the shafts C<SP>1</SP> carrying the rollers c are rotated so as to revolve and turn the bar, and when square bars are being cleaned the roller shafts C<SP>1</SP> are stationarv. When small round bars are being cleaned, a number are placed in the machine and cleaned simultaneously. When cleaning flat plates, suitable idler rollers are placed across the bed parallel with the cam shafts, the idler rollers being sufficiently wide to carry the plates; the cams then preferably consist of parallel sided rollers with suitable projections thereon so as to lift the plate and feed it forward at each revolution of the cams. For sections, suitably shaped rollers and cams are employed. The inlet and outlet to and from the blasting chamber A are provided with vestibules a provided with baffle curtains of rubber and other suitable material to form sealing devices for the chamber.